The present invention relates generally to devices for delivering a drug or other medical preparation to a site within a patient""s body. More particularly, the invention relates to catheters, which deliver drugs or other medical preparations to a site within a lumen of a blood vessel or another cavity within a patient""s body.
Catheters for delivering to a site within a patient""s body a drug or other medical preparation are known. Two such catheters are the Fountain(trademark) Infusion System (Merit Medical Systems, Inc., Utah) and the Cragg-McNamara(trademark) Valved Infusion Catheter (Micro Therapeutics, Inc., California).
One example of the Fountain device is now described. This particular example, catalog number FIS5-135-5 is a 135 cm long tube having a 5 cm infusion segment. The infusion segment is located at a distal end of the device, intended to be inserted into a blood vessel of a patient through a tiny incision or puncture. The Fountain catheter of this example is 5 French (1.7 mm) outside diameter, and accepts through a lumen a 0.035 inch (0.80 mm) diameter guide wire for placement. The infusion segment of the Fountain device includes, distributed uniformly along the length of the infusion segment, a plurality of holes at a density of 10 minute holes each 2 cm, through which a drug or other medical preparation introduced into the lumen, can be infused into the vessel in which the catheter is inserted. The catheter further includes two radiopaque markers at the boundaries of the infusion segment, whereby the catheter is guided using fluoroscopy to the desired site.
An example of the Cragg-McNamara device is now described. Micro Therapeutics, Inc. catalog number 41046-01 is similar to the Fountain device described above. The device is a 5 French (1.7 mm) diameter catheter, 65 cm long, with a 5 cm infusion segment. The lumen of the catheter is large enough to accept a 0.035 inch (0.80 mm) diameter guide wire, and the infusion segment is marked at the boundaries thereof by radiopaque markers. The infusion segment of this conventional device includes, distributed uniformly along the length of the infusion segment, a plurality of holes at a density of 4 minute holes each 2 cm, through which a drug or other medical preparation introduced into the lumen can be infused into the vessel in which the catheter is inserted.
Two catheters with pressure responsive valves, such as slits, forming exits through the wall thereof are disclosed by Appling et al. in U.S. Pat. Nos. 5,250,034 and 5,267,979, both incorporated herein by reference. The catheters of those patents feature a uniform distribution of such exits.
In accordance with the principles of the present invention, there may be provided an infusion catheter having an infusion segment defined to produce a non-uniform distribution of infusion of drug or other medical preparation. The non-uniform distribution of infusion may be produced by a non-uniform pattern of exits, such as holes or slits, defined in the infusion segment. The non-uniform pattern of exits may include plural regions of different uniform distributions of exits. The non-uniform pattern of exits may include plural regions of exits of different sizes, such as slits of different lengths.
According to one aspect of the invention, an infusion catheter comprises: an elongated catheter body defining a catheter lumen, the catheter body having a proximal end at which a medical agent can be introduced into the catheter lumen, and having an infusion segment defined at a distal end; the infusion segment including a non-uniform pattern of infusion exits through the catheter body to the catheter lumen. According to one variation of the infusion catheter, the non-uniform pattern of exits comprises a first region with an exit density of about 1-10 infusion exits per 2 cm of length; and a second region with an exit density of about 25-30 infusion exits per 2 cm of length. In this variation, at least one of the first and second regions can have a substantially uniform exit distribution. Also according to this variation, the second region can be located more distal relative to the first region. Alternatively, according to this variation, the first region can be located more distal relative to the second region. The pattern of exits can vary continuously from the first region to the second region. At least one infusion exit can be smaller than a 30 gauge needle. At least one infusion exit can be a slit. In another variation of this aspect of the invention, the non-uniform pattern of infusion exits can include plural infusion exits of varying sizes. The plural infusion exits of varying sizes can be slits of varying lengths. The non-uniform pattern of infusion exits can include a first region of slits of a first length; and a second region of slits of a second length. The lengths of the slits can be arranged to vary continuously from the first length to the second length between the first region and the second region. At least one of the first and second regions can have a substantially constant slit length throughout.
According to another aspect of the invention, a method of infusing a medical agent into a target lumen of a body, comprises inserting a catheter into the target lumen, injecting the medical agent into a lumen of the catheter, and ejecting the medical agent from the lumen of the catheter into the target lumen of the body at a rate which is not uniform over an infusion segment of the catheter.